The present invention relates to barrel locks and more specifically to an improved barrel lock assembly which is superior in its resistance to theft.
Various types of padlocks and barrel locks have been invented and patented in the past in an attempt to thwart the theft of trailers and other items coupled to automobiles or other vehicles. All of them were of some help but none were totally resistant to attempts to break them. Also various such locks have been used in connection with chains or cables to secure bicycles and other items against theft. The weak link in barrel locks is found in the keyway and detent operating structure within the lock.
A fairly comprehensive history of the background of security locks in general and barrel locks in particular may be found in U.S. Pat. No. 4,711,106 issued to Johnson and reference may be made to that patent for further history and background of the invention.
An object of the present invention is to provide a barrel lock structure which has a pair of generally cylindrically shaped lock body portions, one elongated and generally solid, the other short and generally hollow, and a means for axially locking the two portions together. The means for locking the two portions together includes a spring biased lock structure assembled in one portion of the lock that is movable axially relative to the other portion. The spring biased lock structure includes an axial extension that penetrates the first portion and for spreading a plurality of locking balls apart from each other and thereby lock the two portions together. The spring biased lock structure further includes a detent for engaging a shoulder provided in the first portion.
It is another object of the present invention to provide in a barrel lock structure of the character described above a generally solid cylindrical lock portion which has two sections, the first at one end being of a relatively larger diameter and thereby functioning like a handle or hand gripping portion which may be either smooth or knurled as desired.
It is yet another object of the present invention to provide structure of the character above described wherein the remainder of the first portion is elongated and separated from the first section by a generally conical shoulder and is of a lesser diameter than the first section and than the other lock portion, and the terminus portion of said second section remote from the first section is provided with a machined out cylindrical passageway.
It is yet another object of the present invention to provide in one portion of a barrel lock a plurality of locking balls radially disposed relative to each other, and in the other portion of the barrel lock a corresponding plurality of locking ball apertures adapted to receive a portion of the spherical surface of said balls, the balls being selectively moveable into the apertures, thereby providing a means for locking the first portion to the second portion.
It is still a further object of the present invention to provide structure of the character above described wherein the spheres or balls are movable between one disposition wherein their surfaces can touch and a second position wherein their surfaces are pressed partially into the ball apertures and their cylindrical surfaces cannot touch each other, thereby providing a means for locking the first portion to the second portion.
It is again a further object of the present invention to provide structure of the character above described wherein the second lock portion is of generally the same external cylindrical dimension as the first section of the first portion and there is coaxially disposed within the hollow interior an axially moveable piston, the piston having a stepped shape that includes an axial extension terminating in a conical plunger pointed outwardly away from the main body portion of the axially movable plunger. On the opposite end of the piston, remote from the conical plunger, is a keyway adapted to receive a key of a selected variety.
It is an even further object of the present invention to provide in a barrel lock of the character above described a spring biasing means for biasing the axially moveable piston in one direction away from the locking balls. Additionally, the spring biasing means is supple enough to be overcome by axial force manually imposed in the opposite axial direction to compress the spring and thereby force the axially moveable piston in the opposite axial direction, and to hold the piston in a desired position to engage the detent when said keyway mechanism is rotated cylindrically.
It is an even further object of the present invention to provide in a barrel lock of the character above described an annular groove in the second section of the first portion and a snap-ring inner cylindrical sleeve in the cylinder aperture adapted to mate when the pointer plunger is placed maximally within the said cylinder aperture.
Other objects and advantages of the invention will become apparent from the following description which sets forth, by way of illustration and example, certain preferred embodiments of the present invention.